1. Field of Invention
The present invention relates to planar display and the fabrication method. More particularly, the present invention relates to a display of active matrix organic light emitting diode (AMOLED) and the fabricating method.
2. Description of Related Art
The organic light emitting diode is a photoelectric device and can convert the electric energy into optical form in high converting efficiency and is usually used in an indicating lamp or a displaying panel. Since the organic light emitting diode has many properties, such as no view angle effect, easy fabrication process, low cost, high response speed, full color capable of operating in a wide temperature range, and satisfying the required characteristics of a display for the multi-media world. In recent years, the organic light emitting diode has been one of the hot research topics.
Currently, the active matrix organic light emitting diode (AMOLED) has been greatly developed, wherein the AMOLED typically includes an organic light emitting layer formed over a substrate having a thin film transistor (TFT) array already formed thereon and a cathode layer. In this manner, the AMOLED is driven by the TFT for emitting the light. The convention fabrication method for the display of AMOLED is as follows.
FIG. 1 is a drawing of top view, schematically illustrating a conventional display of AMOLED. FIG. 2 is a drawing of cross-sectional view, schematically illustrating the structure shown in FIG. 1 along the line I-Ixe2x80x2.
Referring to FIG. 1 and FIG. 2, in the conventional fabrication method for the display of AMOLED, a substrate 100 having a light-emitting region 120 and a non-light-emitting region 122 is provided. The light-emitting region 120 of the substrate 100 has already been formed with a number of pixel structures 107 arranged in an array. Each of the pixel structures 107 includes an active device (TFT) and an anode layer 102, a light emitting layer 104, and a cathode layer 106.
In the conventional method, the active device, used to control the pixel structure, is usually composed of TFT""s, of which one TFT is used for switching action and another TFT is used for driving action. The TFT can be amorphous silicon TFT or the low temperature polysilicon (LTPS) TFT. Since the technology for the LTPS TFT can form the driving circuit on the substrate 100 at the same time, most of current displays of AMOLED are using the LTPS TFT as the active device for the pixel structure.
In these pixel structures 107, each one of the pixel structures 107 is controlled by a scan line (not shown) and a data line (not shown). The scan line and the data line, located at two sides of the light-emitting region 120, continuously extend into the non-light-emitting region 122, and form a number of fan-out conductive lines 108. The fan-out conductive lines are used for electrical coupling with the driving circuit formed at the non-light-emitting region 122.
Further still, the driving circuit 110 is formed on the substrate 100 at the non-light-emitting region 122, wherein the driving circuit 110 is electrically coupled with the pixel structures 107 via the fan-out conductive lines 108. Then, a packaging cap 114 is disposed over the substrate 100 by a sealant (not shown) for adhering together. The packaging cap 114 covers the light-emitting region 120 on the substrate 100 and the region disposed with driving circuit 110, so as to prevent the devices of the display from being under a humid environment and resulting in the malfunction.
However, since the fabrication yield for the LTPS TFT is still low, when the driving circuit 110 is abnormal, it is very inconvenient to perform the test or repair on driving circuit 110, which has been formed inside the packaging cap 114. Indirectly, the production yield is also reduced.
The invention provides a display of AMOLED and the fabrication method, so as to at least solve the conventional disadvantages about inconveniently performing the test or repairing on driving circuit, which has been formed inside the packaging cap.
The invention provides a method for fabricating a display of AMOLED. The method includes first providing a substrate, which has a light-emitting region and a non-light-emitting region. Also and, a number of pixel structures are formed in the light-emitting region on the substrate. Each of the pixel structures includes an active device, an anode layer, a light emitting layer and a cathode layer. In the invention, the active device includes at least two amorphous silicon TFT""s or at least two LTPS TFT""s. A driving circuit is formed in the non-light-emitting region on the substrate, in which the driving circuit and the pixel structures are electrically coupled by a number of conductive lines. Then, a packaging cap is disposed over the substrate by an adhering material, wherein the packaging cap covers the light-emitting region but the driving circuit remains being exposed. In the invention, the packaging cap can be, for example, a metallic packaging cap or a glass packaging cap.
The invention also provides a display structure of AMOLED, including a substrate, a driving circuit, and a packaging cap. The substrate has a light-emitting region and a non-light-emitting region. Also and, a number of pixel structures are disposed in the light-emitting region on the substrate. Each of the pixel structures includes an active device, an anode layer, a light emitting layer and a cathode layer. In the invention, the active device includes at least two amorphous silicon TFTs or at least two LTPS TFTs. Also and, a driving circuit is formed in the non-light-emitting region on the substrate, in which the driving circuit and the pixel structures are electrically coupled by a number of conductive lines. Then, a packaging cap is disposed over the substrate and is affixed onto the substrate by adhering, wherein the packaging cap covers the light-emitting region but the driving circuit remains being exposed. In the invention, the packaging cap can be, for example, a metallic packaging cap or a glass packaging cap.
Since the packaging cap of the AMOLED display in the invention does not cover the driving circuit, when the malfunction occurs on the driving circuit, the test or the repairing on the driving circuit can therefore be directly performed.
Since the packaging cap of the AMOLED display in the invention does not cover the driving circuit, the size of the packaging cap can be less than the size of the conventional packaging cap. As a result, the mechanical strength of the packaging cap is improved and diffusion path or area, where the humid air can diffuse into, is relatively smaller.